Have my new engine oil pan. Going to use Permatex "The right stuff" for the gasket material. Upon receiving the oil pan, i noticed even the contact surface was factory painted black. My question is , is it necessary to remove the paint from the contact surface prior to installation......for proper sealing ?. TIA

Nope it's fine to install as is. Just apply a layer of gasket material, install it and only hand tighten the bolts and let it sit 10 mins or so so it has time to start setting up(and doesn't squeeze all the gasket material out) then torque the bolts to spec.

Ahhh , finally a response, that you Brighton !.
Let it sit for a bit , even with Permatex 1 minute gasket? .

As far as letting it sit, if you are using the quick cure stuff I'd let it sit like 30 seconds or so. Apply it, smear it so it's relatively flat on the mating surface of the pan, install, hand tighten bolts, let sit for 15-30 seconds (if you didn't take too long to do the previous steps) then tighten to spec.

You might have to wiggle the dipstick tube out too, I don't know how it's installed on yaris' oil pans but sometimes the tube is held in with an oring that gets stuck.Definitely be careful prying on it, don't want to scar up the mating surface too badly. I'd see if you can use a putty knife to disconnect large portions of it prior to prying at it.

Sorry to be ignorant, but, what does the dip stick have to do with dislodging the engine oil pan from its mating surface.....again, this isn't a dick head response.....I just do not understand. Oddly, the engine oil pan bolts had anti seize on them......didn't know the factory did that ?. I've had this Yaris since new.....June of 2010. This undoubtedly is a peculiar situation. I've tried light prying in conjunction with a Steinal heat gun......no go. Odd , very odd. I'm aware if one is to eager on prying it could damage the mating surface.....FYI.

I haven't looked at yaris's that closely but some cars (subarus) have the oil dip stick tube attached to the oil pan rather than routing the dip stick through the engine like most cars. So I was just thinking it'd be a possible cause of the pan being stuck. I have only seen anti-seize used by mechanics and VERY rarely by factory installs.